MARGARET WARNER: Lt. General Carl Strock commands the Army Corps of Engineers, and the Corps is the agency in charge of repairing the ruptured levees and draining the City of New Orleans.
General, Strock, welcome; thanks for coming here.
MARGARET WARNER: What kind of progress are you making? It's been four days since these levees began to rupture; how much progress are you making fixing them?
LT. GEN. CARL STROCK: As for the levee breaks actually there is considerable good news there. We feel like the situation is stabilized. The flooding essentially is over and now we are in the recovery effort of the flood. We have isolated the levee break areas and we are beginning to repair those areas. So we are having great success with that.
MARGARET WARNER: Now there were three levees that were breached. Are you having to repair them all?
LT. GEN. CARL STROCK: There were actually a number of levees that were over top. The ones we are really focused are the 17th Street Canal and the London Avenue Canal. And we are repairing those. That is the real focus of the effort right now.
MARGARET WARNER: And are you trying to -- are you blocking them off from the lake or are you actually also, are you repairing them on the sides?
LT. GEN. CARL STROCK: Let me explain, there are really four things that are afoot here right now, afoot here: First of all, it's very difficult to get access to the site for even assessments. And so what we've had to do is do a three-pronged approach from the sea, from the air and from the land.
And our objective was to work all three of those, and whatever achieved success first, would be the one that we eventually went with. In fact, all of those are happening. We're building causeways from the land. We're bringing sandbags and other material in from the air to place into the breach, and we're also from the seaside, off the barges driving piles. We're driving piles across the face of the canal that leads to the levee break to stanch the flow of the water.
MARGARET WARNER: And so how long do you think it will be before the levees are at least fixed enough that you can start trying to get the water out?
LT. GEN. CARL STROCK: Well, we're really there now. As it turns out, the geography of the city is such that there is a high side on the Mississippi and then Lake Pontchartrain is actually lower than the Mississippi River. So the gravity naturally pulls toward the lake. And that is how the drainage system is designed.
So what we will do is use gravity where we can by deliberate breaches of the levees to drain the water back into the lake. At the same time, then, we'll get back into the pumping plants that were inundated and bring those back online and then put the pumping on to complete the job.
In fact, the levees that we're working on now, we've sort of stopped work to a degree. The pile-driving we've done across the face of the canals, we want to be sure that we still leave a trail for the water to leave. So we've only driven those piles about 70 percent across the face of the canal, because the lake levels have dropped sufficiently that it's not draining the city. We want to leave that like it is because we can use that avenue to pull water out.
MARGARET WARNER: So you're saying at this point the water in the city is almost going to be higher than the water in the lake.
LT. GEN. CARL STROCK: That's correct.
MARGARET WARNER: And you will be able to use gravity and have it go out.
LT. GEN. CARL STROCK: That's correct.
MARGARET WARNER: Which that isn't the normal condition, right?
LT. GEN. CARL STROCK: No, it is not. Usually the city is dry and below the lake level, yes, ma'am. So what we are doing, then, is, the importance of that point is that we don't want to complete that right now because there may be additional activity. The lake may rise again. So we want to be able to put that barrier in if we need to.
But we want to use that opening to our benefit now to drain the waters out of the lake. So we're really in a pretty good position right now.
MARGARET WARNER: And one other question, because I read in one article that the pressure of the water also makes it just very, very hard to repair the breach. Is that right?
LT. GEN. CARL STROCK: That's correct. There are two types of pressure: Hydrostatic pressure which is stable and doesn't really bother us. But the pressure of moving water is enormous. And in fact, you know and I mentioned three different approaches -- air, land and sea -- the fourth approach is letting nature take its course and really that, the combination of those, what has worked, nature taking its course means the water that was pushed up into Lake Pontchartrain by the storm can only go out so quickly. It's like a large bathtub with a very small outlet. And so that lake level is gradually receding. We knew that at some point the lake level might actually drop before we got the breach closed.
While the water is flowing through the breach, it's very difficult to put anything in the breach that would make a difference. Now that it has stabilized and it is relatively slack water, putting things in the breach works very well.
MARGARET WARNER: Maybe I missed your answer on this, but how much time before you think that you can really start draining water out of the city in a serious way?
LT. GEN. CARL STROCK: We are doing that now. I should say the Corps of Engineers works through the private industry. We let contractors, we bring contractors in. So we mobilize contractors and they work doing the job here.
We are actually in the process of draining levees in St. Bernard Parish, which is over to the east of the downtown, and also in Jefferson Parish, which is a little bit to the west. So we are actually doing that where we can.
I should tell you that the lake, the levee system around New Orleans is actually 13 separate levees, about 300 miles of levee. And not all of those levee cells broke. It is really the ones around Orleans and Jefferson Parish.
Unfortunately the downtown, heavily populated area of it broke. But in the majority of the levees we would characterize it as minor flooding, and we have about, oh, four areas that are significant flooding like downtown.
MARGARET WARNER: I'm going to try one more time to pin you down on any kind of timeframe.
LT. GEN. CARL STROCK: Okay.
MARGARET WARNER: Another general with the Army Corps of Engineers, I think a General Crear, said late today, thirty-six to eighty days before the city was drained, is that it?
LT. GEN. CARL STROCK: General Bob Crear is on the ground, and he works for me, commander at the Mississippi Valley Division. He has a better sense for what is going on. One of the reasons that I'm reluctant to commit on these timings is because if I say something that General Crear has to be committed to, I have got to be very careful about that. This is a very complex thing and there are many variables and sounds to me like General Crear has done more analysis than I've learned about.
But the challenge we have is that how quickly it takes depends on how well the pumps work, are the intakes clear? Can we get the power back to the pumps? As I said, by making nature work for us, we will deliberately breach the levees. If we breach a hundred-foot section of levee it will drain very slow but it's very low risk. We could breach a thousand foot of levee that will drain quickly but there is a risk. And the risk is, if something else comes in, if we have a flood on the Mississippi that dumps water into Lake Pontchartrain, you have another flood event, and we have an open levee, than we've got a problem.
So what we have to do is a risk analysis to determine how many, how large in terms of levee breaks to make. And that will determine the amount of time it takes.
MARGARET WARNER: Finally, today you had a press conference and you said, you all knew that these levees, these miles and miles of levees were really not built to withstand a storm of this magnitude, explain that.
LT. GEN. CARL STROCK: Well, that's correct. When we design a flood protection system, we look at the probability of an occurrence that we are designing against happening.
In this case we designed on what we called a two- to three-hundred year event, an event that only happened that frequency. The way that comes down to probabilities, there's a 99.5 percent chance that that event will not happen or a 0.5 percent chance it will, so a very low probability event in our estimation.
And unfortunately, what we have is that 0.5 event percent that has struck us in that cycle.
MARGARET WARNER: And so what these levees were designed to withstand is a Category 3 hurricane, is that right and the aftermath, but not anything higher?
LT. GEN. CARL STROCK: That's right. It would equate to a Category 3. In fact, this levee system has endured a number of Category 3's and similar type events. We knew coming in as we saw the Category Four and Five hurricane approaching the coast, with a possibility it would make a direct hit on New Orleans, that the prudent thing to do was to evacuate.
So I would say there is a positive aspect to that. And that is that the decision makers made an informed decision about the level of protection afforded by these projects. So they did the right thing to evacuate the city.
MARGARET WARNER: But unfortunately hundreds of thousands of people either couldn't or wouldn't evacuate.
LT. GEN. CARL STROCK: But unfortunately, it was not as effective. Had they not made that decision, we would have a far greater catastrophe on our hands.
MARGARET WARNER: All right, General Strock, thanks, thanks so much.
LT. GEN. CARL STROCK: Thank you, Margaret.